The present invention relates generally to a vehicular headlight, and more particularly relates to the construction of an ornamental frame provided around an inner lens and which is referred to as hood.
In a conventional vehicular headlight, light emitted from the filament of a bulb (light source) is reflected by a reflector so that the light is directed out through an inner lens and an outer lens. The inner lens is disposed between the outer lens and the open side of the reflector, thereby dividing the inner space of the headlight into an outer lens side and a reflector side. An ornamental frame, referred to as hood, is provided between the inner and the outer lenses. The hood is shaped in such a manner that it appears like an extension of the front edge of the reflector. The hood functions so that the inner portion of the headlight near the inner and the outer lenses is prevented from being seen from outside the headlight, which would degrade the appearance of the headlight. The hood is provided separately from the other components of the headlight and then attached to the body of the headlight as well as the inner and the outer lenses.
In general, there are two types of vehicular lamps producing parallel light beams. One lamp type employs a parabolic reflector, and the other an elliptic reflector and a projection lens. The latter type is so-called a projection lamp. Projection lamps are advantageous in that they can be made smaller in size than the former type, as disclosed in U.S. Pats. Nos. 4,677,532, 2,338,901 and 1,581,581.
In a projection lamp, a light source is positioned substantially at the first focal point of the elliptic reflector. The light rays emitted from the light source are reflected by the elliptic reflector and focused by the projection lens. The projection lens is located substantially at the second focal point of the elliptic reflector. The light rays passed through the projection lens are gathered along an optical axis and form a required pattern of light.
Conventionally, since the projection lens is small in size, the lens is covered by an outer lens which is larger in size than the projection lens, and protected by a protector which is mounted along the circumference of the lens in order to obtain a good perspective with respect to the vehicle body when viewed from the outside.
Since the hood and inner lens of the conventional headlight mentioned above are separately provided components, an opening is usually formed between the hood and the inner lens at the time of assembly of the headlight. The reflector must be able to swing through a small angle relative to the body of the vehicle so as to adjust the angle of the direction of emission of the light from the headlight. That is, to enable the adjustment, an adjustment gap is provided between the reflector and the inner lens. If the opening is present between the hood and the inner lens, the adjustment gap can be seen through the opening, degrading the appearance of the headlight. Moreover, the opening lets light leak. Therefore, the presence of this opening produces undesirable effects.
Furthermore, since the hood is a separately provided component, the number of components of the headlight is large, as is the number of steps of assembly of the headlight. Yet further, if the space between the outer lens side and the reflector side is sealed or narrowed, the inner surface of the inner lens or outer lens may be fogged by humid air heated by the bulb. Such fogging creates a problem in that the light rays emitted by the light source are diffused in random directions, thereby causing discomforting glare or reducing the amount of output light. Moreover, since the space surrounded by the projection lens, protector and outer lens is heated by the bulb to a relatively high temperature, the protector and outer lens, which are ordinarily made from a resin, can be deformed due to the heat.